Hydraulic valve gear



Dec. 8, 1936. w. NOBLE HYDRAULIC VALVE GEAR Original Filed April 28,1923 man,

Patented Dec. 8, 1936 UNITED STATES PATENT. OFFICE HYDRAULIC VALVE GEARy Warren Noble, Michigan City, Ind., assigner to General MotorsCorporation, Detroit, Mich., a

corporation of Delaware ReIiled for abandoned application Serial No.

273,592, April 28,'

This application March 13, 1935, Serial No. 10,893

11 Claims. (Cl. 12S-90) v April 28, 1928.

In such systems, it is desirable that air be eliminated from thehydraulic fluid column for most satisfactory operation, as such air,being compressible, affects the proper translation of the plunger motioninto motion of the puppet valve. According to the relative dispositionof the parts such air may accumulate in a high point in the systemadjacent to the plunger or remote therefrom; and it is the object ofthis invention to' provide certain means for effecting and facilitatingthe disposition of such accumulated air in order to avoid thedisadvantages which would accrue if such air were not disposed of.

The invention further contemplates the provision of means' whereby suchair may be bled from any point of air accumulation system in anyautomatic manner, wherebyv the relief of such air from the system willbe effected at a time when the opening of such systems for such reliefwill not materially affect the proper operation of the puppet valve.

Still further, it is the object of the invention to provide means in theplunger operable to control relief flow from a point of air accumulationin the system, whereby such relief will be effected o when` the plungeris in other 'than a puppet valve lifting position and when the column ofhydraulic fluid will not be subjected to the pressures incidental to thepuppet-valve being lifted from its seat.

A further object of the invention is to provide valvular air bleed meansin the plunger together with means effecting the opening of such airbleed means when the plunger is substantially at rest, and inanvinoperative position, whereby -air may be bled from such said systemthrough said plunger during such rest periods.

Still further objects or advantages subsidiary or incidental to, orresulting from the aforesaid objects, orfrom the construction' oroperation of the invention as it may be carried into effect, will becomeapparent as the invention is hereinafter further disclosed.

In carrying the said invention into effect, I may provide a hydraulicvalvegearhaving a cam-operated plunger, a cylinder in which said plungerworks, a puppet valve, a closed hydraulic fluid casing connecting suchcylinder with said puppet valve in such manner thatmovement of hydraulicfluid in said casing by said plunger will effect movement of said puppetvalve, valvular.. means admitting hydraulic valve fluid under pressureto said casing when said plunger is at rest, such as when its followerrides the base circle of the operating cam, a relief valve in saidplunger-opened by a stop when said plunger is so at rest, and meansestablishing communication between said relief valve and a high point ofair accumulation in the hydraulic valve gear system. All of which ismore particularly de. scribed and ascertained hereinafter, by way ofexample, having reference to the accompanying drawing, wherein:

Figure 1 is a sectional, more or less diagrammatic, view of a hydraulicvalve gear system according to said invention.

I and 2 are members which may be part o f the crankcase of an engine,the member I-` carrying a sleeve ila in which is firmly fitted a.cylinder 3. 'Ihe outer end of this 'cylinder has secured thereto a tube4 which leads to a tting 2 5 carried by the spring housing 6 of aVpuppet valve I, this fitting having mounted thereon a tubular extension8 which enters the hollow stem 9 of the said puppet valve, which stem isslidable over the said. tubular extension 8 and is further guided by abushing I0 on the inner end of the spring housing. II is a washer on theouter end of the valve stem 9 between which washer and the shoulder ofthe said bushing I0 a puppet valve vspring I2 is located to normallymaintain the puppet valve closed upon its seat I3.

Slidably in the cylinder 3 is a plunger I4 yieldingly held againstmovementinwardly of the cylinder by a plunger spring I5, and thisplunger is adapted to be moved'into the said cylinder, by

the lobe ls, of a cam l1, through the medium of `the cam follower I8.The cam follower has its walls slotted at I9 to provide clearance for ya transverse bar or stop 20 carried by the member 2. Y

'I'he chamber of the cylinder 3, the tube l, ex-

tension 8, and the hollow valve stem 9 form a opens to a port'23 in thewall of the 'cylinder 3.

The plunger I4 is provided with a passage 2l adapted to coincide withthe said port` 23 when the plunger is at rest and is not actuated by thelobe I6 of the cam as shown in the drawing. The said passage 24communicates, through a passage 25, with a chamber 26 inthe plunger, `inwhich chamber the hollow stem 21 Voi a fluid supply valve 28 works sothat passage of fluid under pressure from the duct 22 to the chamber 26will effect the lifting of the fluid supply valve 28 from its seatagainst the resistance of a valve spring 26 when the plunger is in itssaid position of rest.

having a hollow stem 3l and adapted to be lifted from its seat bycontact of the said stop 20 when the said plunger is in its restposition, as shown,

ly through the actuator tube 4, its other end i `being located in thehollow stem 3 of the puppet valve 1 close to the inner end of the boreof the said stem.

'With the parts arranged as illustrated, the

inner end of the bore of the stem forms a high point in which air mayaccumulate in the system and the tube 35, therefore, establishescommunication between this point of air accumulation and the outlet orrelief valve 30.

It will be observed that thechamber of the cylinder directly beneath theinner end of the plunger may possibly form a point of air accumulation,and the end of the tube 35 entering -a passage 34 of the plunger may,therefore, have suilicient clearance to permit a certain amount of flowsuilicient for the'passage of air between the wallf the said tube 35 andthe wall of the opening It will be apparent from an examination of thedrawing, that flow of a hydraulic fluid through the plunger and past thevalve 28 into the system will induce a flow through the tube 35 from theinner end of the bore of the stem of the puppet valve and out of theplunger past the open relief I valve 30, such flow carrying with it anyair which may have accumulated in the valve stem; and similarly, whereflow is permitted between the wall of the passage 34 and that part ofthe wall 35 which enters the said passage, such flow will also carry tothe relief valve air which may have accumulated beneath the plunger.

It will be understood that the clearance between the tube and the wallpassage 34 is not such that would permit sufficiently free ow to preventilow taking place from valve stem through the tube 35; and it is furtherpreferred that the bore of the-tube 35 be sufficiently small as to be ofa more or less capillary nature where by entrainingA of air to therelief valve may be effected without the tendency of such air to flowback through the tube into the valve stem.

36 indicates a branch from the oil feed duct which may extend to asuitable relief valve (not shown) for the determining of the requiredpressure in the said duct.

When the plunger is actuated by the lobe I6 of the cam, the relief valvestem 3| is disengaged from the stop 20 and the relief valveconsequently- In the base 'of the plunger is a relief valve 30 bleedpipe 35 may be suiiiclently voluminous to permit an amount of oil topass through the system, when the plunger is at rest, sufficient tomaterially cool the stem of the said puppet valve. It is tobe understoodthat this is a secondary object of the bleed pipe 35 to that of the airelimination which it is primarily designed to eil'ect.

This invention may be developed within the scope of the following claimsdeparting from the essential features of the said invention, and it isdesired that the specification and drawing be read as being moreillustrative and not in a limited sense except that as necessitated bythe prior art.

I claim:

l,1. In a, hydraulic valve gear, in combination with a hydraulic uidcasing, valve actuating mechanism including a plunger intermittentlyoperable to exert pressure on fluid in said casing. a cylinder inclosingsaid plunge'r, said'y cylinder having a non-return pressure fluid supplythereto, a relief valve in said plunger opening from a region of airaccumulation in said casing, and valve'unseating means exterior of saidplunger, said means unseating said relief valve when said plunger is inits normal inoperative position.

2. In a hydraulic valve gear, in combination with a hydraulic iiuidcasing, valve actuating mechanism including. a plunger intermittentlyoperable to exert pressure on uid in said casing, a cylinder inclosingsaid plunger, said cylinder having a pressure fluid supply theretocontrolled by said plunger whereby said supply is admitted to saidcylinder when said plunger is in a normal inoperative position, a reliefvalve in said plunger opening from a region of air accumulation in saidcasing, and valve unseating means exterior of said plunger, said meansunseating said relief valve when said plunger is in its normalinoperative position.

3. In a hydraulic valve gear,incombination with a hydraulic fluidcasing,valve actuating mechanism including a plunger intermittently operatingto exert pressure on iiuid in said casing, a cylinder inclosing saidplunger, said cylinder having a non-return pressure fluid supplythereto, a relief valve in said plunger, means for opening said reliefvalve when said plunger is in its normal inoperative position, and awalled passage leading from a 4point of air accumulation in said.

casing, through said plunger.' to said relief valve.

stem of said puppet Valve is slidable, a tubular connection between saidcylinder and said tubular member, and means operating said plunger inits cylinder to effect through a body of hydraulic -point of airaccumulation in said-gear, and means determining the opening of saidrelief valve when said plunger is in a position wherein said puppetvalve is seated.

6. In a hydraulic valve gearthe combination according to claim 4,including a non-return pressure uid supply line to said gear, a fluidrelief valve in said plunger, means establishing com- Ioutside operatingmeans for the second valve to munication between said relief valve and apoint fof air accumulation in said gear, and means determining theopening of said relieivalve when said plungerv is in a position whereinsaid puppet valve is seated.

7. In a. hydraulic valve gear, a hydraulic iluid casing, an actuatorcomprising a plunger operating againstviluid in the casing, a puppetvalve having its stem exposed to the iluidwhereby a change in pressuremay operate the valve,al pair of iluid control valves in the plunger,a'walled iluid supply passage leading to one of the lastli;` mentionedvalves, a walled fluid passage leading a plunger therein, a plurality ofspring biased valves in the plunger, a source of iiuid pressure supply,a channel in the plunger to one valve from actuate the same.

9. In hydraulic valve gear, a fluid casing, a plunger operable withinthe casing, a puppet valve having a hollow stem relatively movable atone end of the fluid casing, a supply and a relief valve in the plungeralternately operable, and a tubular air bleed connecting the top of thehollow portion of the valve stem with the relief valve to remove theaccumulated air therefrom.

p 10. In hydraulic valve gear, a hydraulic casing, va plunger therein, aplurality of separate valves k*therein independently spring biased toclosed position, means supplying pressure for opening one of said valvesand means to open the other of said valves.

11. In a device of the class described, in combination with a closedhydraulic fluid casing, an actuator cylinder, a plunger in said actuatorcylinder, an air bleed valve in said plunger, control means for the airbleed valve, and means in the plunger supplying uid under pressure tosaid casing, said supply means being -sensitive' todifferential pressurebetween said uid supply and uid in the casing.

" WARREN NOBLE.

